Risk Analysis for Rock Slopes in Open Pit Mines. Part II. Limit Equilibrium Analysis for Rock Wedge Stability

摘要

Instability of rock slopes often occurs in the form of excessive movement of bodies that are bounded by discontinuities. The well-known limit equilibrium analysis for wedges and blocks suffer from procedural simplifications and from the basic deficiency of limit equilibrium analysis--the rigid body assumption. Thus, stability analysis for two- and three-plane wedges with a wide range of additional features regarding failure mode and external forces have been developed. The deficiency, due to the rigid body assumption, was corrected by an approach that includes the effects of the in situ stress field and of the stiffness of discontinuities. The final step in making limit equilibrium approaches more valid was achieved with artificial supports which makes it possible to identify the most critical failure mode and to determine the corresponding factor to safety. The analytical development includes the creation of appropriate computer codes and routines for programmable pocket calculators.